Just read a great fan theory that makes some sense.
Talks about Kylo's master plan to confront And destroy Snoke with Rey's help. He was sincere in saying help me to Han, by allowing him to sacrifice him for the greater good in order to convince Snoke that he is worthy to delve deeper into the Dark Side. This sacrifice will enable him to get closer to Snoke in person. He needs Rey's power to balance the light and dark in a united front against the core of evil in Snoke. He offers to train her during the light saber duel.
The story arc may involve the alliance of all the new characters to finally confront the dark side in VIII and IX
http://uproxx.com/movies/star-wars-kylo-ren-theory/
Another nugget as to the mystery of Snoke. Could it be he is an evil Sith spirit of the dark side of Anakin?
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Perhaps when Kylo looks at Vaders mask and says he will complete what you started. He is speaking to Anakin when he turned against Palpatine in ROTJ.